It's an interesting question because same thing happens with lots of "expensive toys"...the Playstation 2 had the same issue when it came out. Same thing for the 1D. Manufacturers don't want to build up huge stocks before they start shipping new products and they tightly control the price at which the stuff is sold. Clearly demand far exceeded demand for the D60, 1D and Playstation 2, yet instead of raising price to lower the demand and equate demand and supply, manufacturers kept the price where it was and allocated the limited supply in a particular way.
It's weird to hear people complaint at the same time about (1) how expensive these things are and (2) that manufacturers can't keep up with demand. If (2) happens, the only solution would be to *raise* price even further and lower the demand to the point where supply can meet demand.
In that sense it's definitely a "marketing strategy" to keep prices artificially low. But I don't see any reason why manufacturers should limit supply and shipment when demand clearly exceeds the chosen supply level, as the only reason you would ever want to limit supply is to keep prices at a certain level (which they don't need here since demand is far greater than supply).
There are some instances where companies do that, for example supply of business class seat, number of seats in sports arenas, certain luxury products, etc. However, it doesn't seem to make any sense in this case.
Philippe